when I use For loop, key pass the next step. while the foreach data did not changed data.PHP - php

Question

This is my function, which to calculate the intersection time range of two people. when I use three loops, the first loop could pass the key to the next step, but the data they used belong to other people's data. I am very confused.
public function test()
{
//choose records of viva arrangement
$records = DB::table('application_student')
->where('allocationStatus', '=', 1)
->select('user_id', 'supervisor_id', 'assessor_id')
->get()->toArray();
//single records
foreach ($records as $key => $record) {
$viva[] = [
$sup_id = $record->supervisor_id, // key 0=>supervisor
$stu_id = $record->user_id, // key 1=>student
];
}
// $x is the key number of viva[]
for ($x = 0; $x <count($records); $x++){
$sup_id = $viva[$x][0]; //supervisor_id of record $x
$stu_id = $viva[$x][1]; //student_id of record $x
//find availability of supervisor
$sup_time = DB::table('time_allocates')
->where('user_id','=',$sup_id)
->select('start','end')->get()->toArray();
//find availability of student
$stu_time = DB::table('time_allocates')
->where('user_id','=',$stu_id)
->select('start','end')->get()->toArray();
//every single availability of supervisor
foreach ($sup_time as $key => $supT) {
$sup[] = [
$s1 = strtotime($supT->start), //key 0=>start time
$e1 = strtotime($supT->end), //key 1=>end time
];
}
//every single availability of student
foreach ($stu_time as $key => $stuT) {
$stu[] = [
$s2 = strtotime($stuT->start), //key 0=>start time
$e2 = strtotime($stuT->end), //key 1=>end time
];
}
//$i is the key number of single supervisor availability record
for ($i = 0; $i < count($sup_time); $i++) {
//$j is the key number of single student availability record
for ($j = 0; $j < count($stu_time); $j++) {
echo "$x+'$i'+'$j <br>";
$sup_s1 = $sup[$i][0]; // start time of supervisor
$sup_e1 = $sup[$i][1]; // end time of supervisor
$stu_s2 = $stu[$j][0]; // start time of student
$stu_e2 = $stu[$j][1]; // end time of student
//make sure the time range of student between supervisor has intersection
if($stu_s2>=$sup_s1 && $sup_e1>$stu_s2){
$start = $stu_s2;
if ($sup_e1<=$stu_e2){
$end = $sup_e1;
}else{
$end =$stu_e2;
}
if ($end-$start>=3600){
$start_date = date('Y-m-d H:i:s', $start);
$end_date = date('Y-m-d H:i:s', $end);
echo "$start_date '-' $end_date -$stu_id -$sup_id<br>";
}
}elseif ($sup_s1>=$stu_s2 && $sup_e1>$stu_s2){
$start =$sup_s1;
if ($sup_e1<=$stu_e2){
$end=$sup_e1;
}else{
$end=$stu_e2;
}
if ($end-$start>=3600){
$start_date = date('Y-m-d H:i:s', $start);
$end_date = date('Y-m-d H:i:s', $end);
echo "$start_date '-' $end_date -$stu_id-$sup_id <br>";
}
}
}
}
}
}
this is the result of the window. the student id changed from 2 to 3, but the data use the 2 always. please help me, guys.
enter image description here

Answer 1

You're not reinitializing $sup for each loop.
$sup[] = [
$s1 = strtotime($supT->start), //key 0=>start time
$e1 = strtotime($supT->end), //key 1=>end time
];
Same for $stu[]
for the second student, it will add the data on top of those of the first one.
You need to do it like this
//every single availability of supervisor
$sup = [];
foreach ($sup_time as $key => $supT) {
$sup[] = [
$s1 = strtotime($supT->start), //key 0=>start time
$e1 = strtotime($supT->end), //key 1=>end time
];
}
//every single availability of student
$stu = [];
foreach ($stu_time as $key => $stuT) {
$stu[] = [
$s2 = strtotime($stuT->start), //key 0=>start time
$e2 = strtotime($stuT->end), //key 1=>end time
];
}
PS: you have a lot of redundant code and many extra loops to remove.